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Re: the more diversity the better?



Some points I would like to make:

1) We often measure species diversity by plant species, i.e., 
Redwoods,  Sphagnum spp.  However, my view of the ecosystem that I 
think is more successful is the understanding that animals, etc. are 
part of the ecosystem and play their role in the ecosystem whole.  A 
question I have is why do we as humans not include the animal kingdom 
as a significant part of the ecosystem?

Much of the United States land area (2/3rds) has a natural tendency 
to shift to simplicity, if disturbance were removed (I call this 
conscience decision to remove disturbance the tool of rest).  We often 
associate this disturbance as being fire and perhaps, technology applied 
by humans.  However, living organisms are also a way of causing 
disturbance in the ecosystem.

Did you watch Dances With Wolves and the scene with the passing herd 
of bison?  This was only a small herd, about a thousand, that created 
the swath in the landscape.  At one time, there was 60 million bison 
on the continent, by some conservative estimates.  Early European 
settlers wrote of finding a high knoll to stay on while bison passed 
them for five days!

The United States land area had huge populations of bison, elk (prairie 
elk which were supposed to be double the numbers of bison), antelope, 
deer, and other species several thousand years ago that would amaze us in 
terms of complexity.  In association with these herds were predators, 
wolves, bear, cougar, humans.

There had developed, over time, immense complexity, variation, and 
volume of species (plants included).  We replaced these migrating 
herds with equivalent numbers of stationary herds of cattle, sheep, 
goats, and even elk, bision, antelope and deer (look at the tragedy 
of Yellowstone Park).

Many of the National Parks and Monuments in the Southwest are 
becoming deserts today, created by our belief that animals are not 
part of the ecosystem.  Areas of once thriving grasslands and perennial 
streams are becoming areas of blowing sand, parched soil, dry stream 
beds and simplicity of species.  Humans are creating simplicity due to 
the paradigms that the animal kingdom is foreign to the ecosystem.

2) The role time plays in diversity.  We measure time as a function 
of our lifespan.  The Redwood trees live 1500 years plus.  That's 
longer than Europeans have been in America, by three times.  Redwoods 
wear out, die of old age, and fall down creating a incredible change 
in the relationship of light on the forest floor.  New diversity 
springs from this passing of the old tree.  As I have stood as a 
midget in the Redwood forests, I have thought about being a midget in 
time as well.

"We see the world as we are, not as it is".  I am often reminded of 
that thought when pondering about the ecosystem.

> To:            sgh1@cornell.edu
> Cc:            gale-sinex@aae.wisc.edu, sanet-mg@amani.ces.ncsu.edu
> Date:          Sun, 17 Nov 1996 18:06:25 PST
> Subject:       the more diversity the better?
> From:          jvworstell@juno.com (James V. Worstell)

> Are there any ecologists on this list who can discuss "positive feedback
> switches"? Many plant species change their environment to make it more
> suitable for themselves and in so doing decrease diversity--Coastal
> redwoods being a primary example cited by many.  An extreme example:
> Sphagnum spp create "monocultural" bogs from ponds--almost eliminating
> diversity and helping more of their species survive.   Many ecologists
> see stability as associated with lack of diversity.  Where ecosystems
> are regularly disturbed, diversity is usually far higher, according to
> the studies of Reice and others.  Extreme diversity and disturbed,
> chaotic physical conditions go hand in hand in nature.  Many (or can we
> say most?) species fight  such extreme diversity by creating a stable
> environment more conducive to their kind.  Diversity increases as
> stability decreases.
> 
> While decrying the pesticide-laced Illinois cornfield or Mississippi
> cotton field, one need not  make the inferential leap to "the more
> diversity, the better."
> 
> If these species had listservs they'd probably not say "diversity is bad"
> 
>